Sunday, November 28, 2010

Friday's post drew out the true-life testimonies of two CTC readers -- convincing proof once again that Ringtail isn't a fairy tale fabrication.

Entomologist Michael Collins' comment brought back fond memories of collecting days with some mutual friends and mentors, and it came with the photographic proof seen above.

Here's his tale . . .

"I had in 1988 a humorous encounter with a ringtail while blacklighting near Lake Pena Blanca in the Atascosa Mts. west of Nogales AZ .

It was a moon-less night, best for blacklighting for saturniid moths (my specialty), and the world was very dark beyond the blue glow of the light and sheet.

Nevertheless, I thought I saw a shape quickly moving through the brush, right at the edge of the steep rocky cliff near which I had set up my light.

I began shooting in the direction of the movement with my Nikon film camera, not sure I had recorded anything.

I did notice that several large sphinx moths began disappearing from the ground around the sheet!

On getting the prints back a week later I first admired the thick black-and-white tail that I captured exiting the frame, flipped through the prints, and found I had by good luck caught a ringtail in decent focus, who was in turn focused on taking the best moth specimens that were coming in.

These neat little animals are probably common in the Yuba River canyon near my home in Nevada City, where 49er prospectors called them "miner's cats", but I have never seen one in the wild in all this time in California.

The Arizona sighting was a rare and special treat."

If it's scientific exploration in the field that turns you buy Dr Collins' memoir -- Moth Catcher: An Evolutionist's Journey Through Canyon And Pass, and check other interesting titles listed in the University of Nevada Press's Holiday Sale (click on Sale). The prices are right!

We learned that Texas ringtails eat juniper berries in winter. Now we're cam-trapping the juniper woodlands.

The elusive quarry inevitably comes up during Chimineas rendezvous.

On some some dirt road to nowhere it's -- "Hey look at those cliffs over there -- looks like ringtail habitat".

It comes up during happy hour.

"I swear, they're all over the place in Butte and Plumas County." I saw a dead one on Rt 70 last week, and even the kid at my local hardware store knows their favorite bait."

"Whats that?' Craig rises to the bait.

"Strawberry jam."

"We're using all fruit jam."

"No wonder we're not having any luck."

The team collects the camera traps the week before Random Truth and I arrive.

They scope out the pictures in the field, which is one of camera trapping's simple pleasures.

Back at the lab they download the memory sticks and view the photos again on the computer to see if they missed anything.

When the photos are found wanting of ringtails Craig slides into a blue funk.

Fortunately, he's a busy man and the blues don't last long.

A few days layer we all meet and our 3-day camera trapping session begins.

These are generally convivial reunions, but we rarely have time time to set all the cams.

When we part ways Craig is jazzed to cast off with Todd and Heather to set the remaining ones.

After the last session he sent me this email.

"Lucky we didn't try to get to Hunt Spring when you were out here. It was a hell of a hike and the canyon with the spring was so steep and choked with brush, we couldn't get down to it. I might try to get down there in cooler weather.

As it was, we left the truck at about 2:30 in the afternoon and got back at close to 8:00 pm. We hiked the last portion in darkness. It was still very hot (mid-90's) this past week and we brought plenty of water.

However, it was still a strenuous hike and Todd ended up overheating and upchucking. I felt bad for him but we sat in the shade until he felt better and we headed back to the truck.

We actually set the cam in a very interesting spot. We found a large expanse of rock outcrops overlooking Gypsum Canyon and surrounded by chamise scrub. It's similar to the spot where we got Spilogale last time. I am encouraged because the canyon it overlook is more mesic that most of the stuff on Chimineas proper. I could see sycamores growing in the canyon bottom. It looked ideal for ringtails but the proof is in the pudding. Let's wait and see what we get."

I have to admire those plucky guys. Nothing like cooky-tossing dedication. And I should mention that Todd's the one who hauls the pack.

To hither an yon

We checked Craig's set when we arrived at the ranch.

An impenetrable expanse of chamise blocked their access to Hunt Spring, so they set the cam on a beautiful outcrop.

I would have selected the same place.

Craig at the set above Hunt Spring

But only two critters mugged for the camera -- right on that boulder in front of Craig.

Sunday, November 21, 2010

The location on a trail in Marin County wasn't far from a steep year-round creek with prominent step pools.

Habitat: coastal mixed confer and deciduous forest. Lots of lichen and mossy trunks, and the bracing scent of bay laurel.

I regard any species of Dicamptodon with animistic reverence, not just for their size -- up to a foot, but for their bark, bite, and ruggedly handsome good looks. Not to mention their penchant for gobbling banana slugs, small snakes, shrews and mice.

Dicamptodon is an icon of our moist coastal forests and an indicator of watershed health.

The number and biomass of their stream-dwelling larvae often exceed that of salmon.

But you don't often see adult metamorphosed Dicamptodon unless you get your jollies removing old road culverts, wandering the woods on rainy nights, or dissecting the nests of Pomo tree mice.

Not that encountering Big Sally doesn't happen now and then in other ways. Finding terrestrail Dicamptodon is serendipity for some, and a quest-worthy adventure for others.

In the 1940s a well digger named Dan Coon flushed several of the seldom seen sallies out of springs in the Santa Cruz Mountains.

The discovery fueled the imagination of herpers young and old.

We viewed Dicamptodon as a deeply fossorial Orpheus that climbed out of the underworld only in darkness, and perhaps only on rainy nights.

Its nocturnal peregrinations could only be accounted for by a Swiss made circadian clock and a supernatural ability to sense meteorological changes deep in the earth.

Latter day Dicamptodon enthusiasts however found that its subterranean retreats included root channels and the burrows of fossorial rodents, usually about 3 feet deep.

This was a disappointing finding for old boy naturalists, but ecologist Gary Fellers and coworkers recently bolstered our somewhat diminished awe.

When Point Reyes National Seashore replaced 4 old rusty culverts with bridges for the restoration of salmon streams, biologists were required to stand vigil and assess habitat for the federally protected California red-legged frog (Rana draytonii).

While bearing witness to back hoe and dozer the researchers discovered assemblages of 23 and 27 metamorphosed Dicamptodon under two of the culverts.

Amazing, huh?

And that's not all.

Recent investigations of tree vole nests by Eric Forsman and James Swingle uncovered an old record of a large Dicamptodon cohabiting with a litter of Pomo tree mice -- 2.4 meters above ground.

Okay, back to the raccoon . . . it probably discovered big sally on the trail after a recent shower.

If Sally bit, barked, thrashed, and released noxious compounds in self defense, the ploys didn't change the fatal course of events.

Those sensitive coon paws probably gave Sally a rude rubbing and rolling before the jaws clamped down.

[Nota Bene: For the sake of names dropping, I might add that Mr. E.S. Dethlefson, Mr Coon's friend who recognized the significance of the flushed salamanders and published the report, lived down the road from my grandparents house in Ben Lomond, California. Here's a bit about my early days there.]

Friday, November 19, 2010

Getting a half-way decent shrew picture is an occasion for jubilation and a bottle of beer.

And this, kind readers, appears to be a Fog shrew (Sorex sonomae) -- two-tonedandin the middle of its fall molt. From the wilds of Marin County,

Bewitching, wouldn't you say?

Did I hear someone say BS?

Okay, I don't know it's a Fog shrew for certain, because shrews are buggers to identify and it helps if you're nearsighted.

You really need to get their skulls out of their heads, or at least give them a microscopic dental exam.

But among Western North American shrews the Fog shrew is a biggie -- up to 150 mm in total length, and if you know the size of big leaf maple leaves, like the one next to this shrew, then you know this is a big shrew.

The Fog shrew also has a unicolored tail, while most western shrews have bicolored tails with much darker dorsal surfaces.

An identity crisis has dogged this shrew for many years.

Hartley H.T. Jackson, who by the way wrote his first scientific paper at the tender age of 15 when most boys are doing other things, called it the Pacific shrew (Sorex pacificus).

But not for its peaceful disposition. It's at home in the cool coastal forests from northern Oregon to Marin County in California.

Three and a half decades later a young Jim Findley demoted it from full species to a subspecies of the puny but more widespread Wandering shrew (Sorex vagrans sonomae). It was the macro-shrew at the end of the Rassenkreis.

The late medical doctor-mammalogist Murray Johnson and B.T. Ostenson took issue with that decision, but the demotion stuck for forty-five years.

Then Leslie Carraway, a high-powered lady from Texas with an obsession for shrews concluded that it was not the wandering vagrans.

She elevated its rank to the foggy sonomae, and for the time being her word is final.

Such is taxonomy.

Christian and I set the camera close to the ground at a small spring that debouches from a patch of ferns.

We were lucky.

If you want to camera trap shrews you really have to enter the netherworld of duff and detritus.

Wednesday, November 17, 2010

"Whenever the pressure of our complex city life thins my blood and numbs my brain, I seek relief in the trail; and when I hear the coyote wailing to the yellow dawn, my cares fall from me - I am happy."

I myself had never heard of Barn Owls foraging on foot, although it wouldn't totally surprise me. This species, however, is so highly aurally inclined in its hunting that infantry-style foraging would be a surprise. Do you have videos? All owls, having pounced on prey and missed, do a certain amount of walking about and weaving their heads from side to side to obtain auditory clues, and all seem to be far-sighted and therefore back up from the point of impact and try to locate the prey by sight.

I quickly googled up a minor paper at http://www.fosbirds.org/FFN/PDFs/FFNv26n3p91-93McMillian.pdf which seems to present pretty good evidence of foot hunting by Great Horned Owls, and it mentions other references (though I couldn't locate any discussion of the phenomenon in Johnsgard, which the author mentions. I am also not entirely convinced that his owls actually ate the tern eggs; eggs of ducks and coots not infrequently turn up undamaged in GHO nests, having slipped out of the bodies of prey brought there. Such eggs are not eaten and become part of the nest detritus.

At any rate, if you can provide more detail or video of the foraging on foot that you have seen, I would very much like to see it.

Then came another message . . .

While ruminating about your pedestrian foragers, I remembered that I have seen Burrowing Owls hunt crickets on foot during the day; of course that species is highly visually oriented and more or less cathemeral, so that's no great surprise. The Eurasian Tawny Owl, however, is completely nocturnal but also forages for earthworms on foot sometimes (I've seen Red-shouldered Hawks do so in the daytime, rather surprisingly, since it's such insubstantial prey for such a large raptor).

The codger was highly gruntled with the finding, and began daydreaming about ways of getting the evidence in video.

The problem was time. The days were getting shorter and we hadn't even scheduled the next trip to Chimineas.

Meanwhile, Craig succumbed to curiosity -- he hauled his live traps to Barny's stomping ground, and though he caught deer mice and pocket mice in the neighborhood, harvest mice were the only mice in the swale.

Once again I poured over the photos searching for some hint of the elusive quarry . . . some telling crumb of evidence in the corner of Barny's beak, like the spurred femora of a Jerusalem cricket.

At last I found some frames of suspicious activity -- Oh my God! -- frames of Barny holding something fuzzy in her beak.

I dragged the jpeg into Photoshop and zoomed in.

The victim was no wee mousie -- but the seed head of annual rabbitsfoot grass, Polypogon monspieliensis.

There was actually a sequence -- Now Barny was gripping a seed head in her talons.

Then she was either eating it or tearing it apart!

Was Barny pouncing on imaginary mice in the form of grass seeds?

And sampling them for texture and digestabilty?

The swale seemed a strange and risky place for Barny to hone her hunting skills, if that is what she was doing.

A predator could explode out of the grass and catch the owl in the midst of her baffling game.